Method to assess reservoir continuity between single wells in an oilfield formation within a region with several petroleum reservoirs

Abstract

A method to assess reservoir continuity between single wells in an oilfield formation within a region with several petroleum reservoirs, including the steps: collecting water samples from each of the single wells, obtaining the geochemical composition of each of the water samples, obtaining a dataset from the geochemical compositions of the single wells, analyzing the dataset using principal component analysis to obtain principal components of the dataset, clustering the principal components to obtain clusters, identifying hydrodynamic groups from the clusters, assigning the wells to hydrodynamic groups, wherein wells within one single hydrodynamic group are considered to be hydraulically communicated.

What is claimed: 
     
       1. A method comprising:
 collecting a plurality of water samples from a plurality of wells in a reservoir region, 
 obtaining, using a geochemical analysis with the plurality of water samples, a geochemical dataset describing a plurality of geochemical compositions of the plurality of wells, 
 determining, by a computer processor, a plurality of principal components based on the plurality of geochemical compositions and a principal component analysis, 
 wherein the plurality of principal components represent at least some of the geochemical dataset including a plurality of geochemical ratios comprising a calcium-to-magnesium ratio (Ca/Mg), a strontium-to-calcium ratio (Sr/Ca), and a sodium-to-chloride ratio (Na/Cl), representing the geochemical dataset using the plurality of principal components to obtain a reduced geochemical dataset, 
 clustering, by the computer processor and using a k-means clustering algorithm, the reduced geochemical dataset to obtain a plurality of clusters, 
 identifying, by the computer processor, a plurality of hydrodynamic groups within the reservoir region from the plurality of clusters, 
 wherein the plurality of wells are assigned to a respective hydrodynamic group among the plurality of hydrodynamic groups based on the plurality of principal components, 
 determining, by the computer processor, a plurality of hydrocarbon production potentials for the plurality of hydrodynamic groups using the plurality of clusters and a plurality of tectonic structures in the reservoir region, 
 determining, by the computer processor, a location of an exploratory well within the reservoir region based on at least one hydrocarbon production potential among the plurality of hydrocarbon production potentials, and 
 performing a drilling operation at the location of the exploratory well. 
 
     
     
       2. The method of  claim 1 , further comprising:
 coupling the plurality of hydrodynamic groups with pressure, volume, and temperature (PVT) testing data of the plurality of wells, wherein positively tested single wells in a hydrodynamic group among the plurality of hydrodynamic groups are considered to be hydraulically communicated, and negative PVT single wells in the plurality of hydrodynamic groups are considered to be hydraulically compartmentalized. 
 
     
     
       3. The method of  claim 1 , further comprising:
 coupling the plurality of hydrodynamic groups with a plurality of structural features of an oil-field formation, wherein two hydrodynamic groups among the plurality of hydrodynamic groups without a structural feature between them are considered to be hydraulically communicated, and a portion of the plurality of hydrodynamic groups with a structural feature between them are considered to be hydraulically compartmentalized. 
 
     
     
       4. The method of  claim 3 , wherein the plurality of structural features comprise faults, fractures, and dikes. 
     
     
       5. The method of  claim 1 , wherein the geochemical dataset comprises a pH parameter and a density parameter. 
     
     
       6. The method of  claim 1 , wherein the geochemical dataset comprises water hydrochemistry data, wherein the water hydrochemistry data describes total dissolved salinity (TDS). 
     
     
       7. The method of  claim 1 , wherein the plurality of water samples are filtered by applying filtering criteria to detect potential contamination of a water sample among the plurality of water samples and to select a representative water sample from each well among the plurality of wells. 
     
     
       8. The method of  claim 7 , wherein the filtering criteria is based on elevated concentrations of potassium to detect the potential contamination of the water sample. 
     
     
       9. The method of  claim 1 , wherein the reservoir region is a gas or an oil reservoir. 
     
     
       10. The method of  claim 1 , wherein the plurality of principal components are weighted before the plurality of principal components are clustered.